The maximum time in seconds to wait for a connection attempt
to succeed before returning failure. Note that if
max_execution_time has been exceeded when a connection attempt
times out, your script will be terminated before it can take
action on failure. The default is one minute.

The maximum time in seconds to wait for a select_db or query
operation to succeed before returning failure. Note that if
max_execution_time has been exceeded when an operation times
out, your script will be terminated before it can take action
on failure. The default is no limit.